2019 · Q81
A 12 m long wire is cut into two pieces, one of which is bent into a circle and the other into a square enclosing the circle. What is the radius of the circle?
Elementary MathematicsMensuration
- A12/(π + 4)
- B6/(π + 4)
- C3/(π + 4)
- D6/(π + 2√2)
Explanation
The square encloses the circle, so its side equals the circle's diameter 2r. 2πr + 4(2r) = 12 gives 2r(π+4) = 12, so r = 6/(π+4) m.